Top OPENAPI GitHub Repositories & Tools (2026)

🗹 TypeScript HTTP Framework focusing on e2e type-safety, easy setup, performance & great developer experience

😎 A list of awesome projects related to OpenAPI 3.0.x, curated by the community

Generate OpenAPI schema from RSpec request specs

Template to build modern web apps with a classic REST API. Ideal if you need offline & real-time features on day one.

Lightweight embeddable web server written in pure C# with few dependencies to 3rd-party libraries.

API package for code generated by Swift OpenAPI Generator.

URLSession transport for Swift OpenAPI Generator.

Ollama SDK for .NET

C++23 client for Kalshi's Predictions API. Created from Kalshi's OpenAPI and AsyncAPI specs, it covers every REST operation and WebSocket channel. The WebSocket client reconnects and resubscribes. Optional transports add retries and rate limiting.

Modern data layer for TypeScript apps - type-safe ORM, built-in access control, automatic query services

The open source, no-code MCP Server for AI-Native API Access

A RESTful framework built on top of light-4j with both Swagger 2.0 and OpenAPI 3.0 supports

Transforms a Hydra API doc in an intermediate representation that can be used for various tasks such as creating smart API clients, scaffolding code or building administration interfaces.

Open-source OpenAPI mock server with cloud hosting and local modes for development, testing, and CI. Generates realistic API responses from specs with latency simulation, error injection, proxy fallback, and request validation. Validated against 2,200+ real-world OpenAPI specs.

Extensions for Microsoft.AspNetCore.OpenApi

Python client for the Datadog API